Thexder was one of the first arcade games to hit the IIGS, released by Sierra
who translated and converted the game for Western audiences from the Japanese
original by Game Arts.

Thexder is a platform game and borrowing from popular
elements of giant robots of the 80s, its main claim to fame being that you
can transform from a robot to a plane and back again to overcome foes and obstacles.
This newer version supports joystick, but I find using the keypad for directional
controls with open apple as the fire button and option to kick in the shield,
better.

The controls may take a little time to get used to, especially in regards
to how you transform from robot to jet. There are about two dozen different
types of enemies and you'll be experimenting to find their weak points. You
fire a laser beam which is heat seeking: sometimes good, sometimes bad. Just
make sure you engage the enemy without having to fire upon non-hostile heat
emitting objects that would otherwise waste your energy and draw your fire
to the wrong target. Tip #1: if you press space bar in either robot or plane
mode, you will suspend in air and can shoot in that position. Tip #2: there's
no need to use the shield. I've played through the entire game several times
without using the shield. Using the shield will not give you the bonus recharge
and increase the energy maximum you receive at the end of each level, which
became far more useful in later levels.

If the music bugs you, cool but repetitive
as it is, press "M". "S" kills
the sound.